We stayed at Hotel Alpenrose Wengen which can be easily found on the web if you type in a search. They have their own reservation site. I usually reserve directly with hotels as much as possible as they take responsibility if something goes wrong with the reservation on their side. If booking from an external party and there is a mistake on the other party's side, the hotel says it is not their fault.
Reviews and more photos on Alpenrose Wengen can also be found on Tripadvisor. Be sure to reserve the rooms on the South Facing side. Also definitely advisable to book the Half Board with a very reasonably priced 5 course dinner. Without a car, it will be inconvenient to find a place for dinner around there.
The hotel offers a pickup shuttle from the train station. You only need to give them a call - the free phone is located on the station foyer - when you face the station office, look to your left. There is a open foyer and you will see the phone with a large signboard showing all the hotels. Each hotel has a number assigned to it - just pick up the phone and call that number (it's not the official tel number but just a number assigned to Alpenrose). They will come and pick you up.
Sorry I can't help with apartments in Wengen as we have always stayed at Alpenrose. But I am sure an apartment would save you quite a bit as compared to a hotel.
The walk to hotel Alpenrose passes by the supermarket and then downhill for about 10 minutes. Going uphill back to the station isn't a problem without luggage (we are seniors above 60 and managed). They can even drop you off at the station if you give them advance notice of around an hour.
You can view some photos on my trip reports when we first visited Wengen::
The Panoramic walk from Mannlichen to Kleine Scheidegg (take the cableway from Wengen up to Mannlichen) is one of the most beautiful walks, with the Eiger, Monch, Jungfrau facing you as you walk. This is one walk we would like to repeat if we ever get the chance. Remember to walk in the direction towards Kleine Scheidegg and not from K so you get the majestic views in front of you. There is a cafe (cafe Grindelwald Blick) just before you end up in Kleine Scheidegg. I have no idea why they gave the cafe that name as it's not in Grindelwald.
Another ride that is quite scenic is from Mannlichen to Grindelwald. It is a long cable car ride (don't stop at the middle station but go all the way to the end) with green fields below and the alps in view. When you reach the Grindelwald cable car station, just take a bus all the way to Grindelwald First bus stop. From there, you go up to First and do the zipline or trotti bikes if the children are up to it (we skipped the activities). We didn't like the cafe up in First as the food was cold and microwaved - not worth it. The Thrill walk in First can't be compared to the Birg bridge in Murren. For us, the First experience was ok but we probably won't repeat it. Perhaps the children may enjoy the activities.
After the Panoramic walk, you can take the train from Kleine Scheidegg back to Wengen (sit on the left).
We only visited the Big Thrill Walk in Murren on our 2nd trip so I haven't done a report yet. If you and the family aren't afraid of heights, then this is an experience I highly recommend. As with all outdoor trips, check the weather report so you can plan accordingly. That's why it is better to have more days in one region so your options are not so limited due to unpredictable weather.
Murren itself is quite lovely if you sit at a cafe and enjoy a drink in the open - just soaking in the mountains which are really so very close. We enjoyed the patio at Hotel Alpina (but stayed at Hotel Alpenblick) in the afternoons.
If you like, you can actually base yourself in Wengen and Murren which is what we did on our 2nd trip last September.
In Wengen, you can go up to Mannlichen, walk around and do the Panoramic Walk to Kleine Scheidegg. You can also make a trip up to the Jungfrau if the weather is good. We enjoyed that experience too. On another day, take the long cable car ride to Grindelwald and bus to First.
When you base yourself in Murren, it's much easier to get to the Birg Thrill Walk or Schilthorn. You can even walk down to Gimmelwald and take the cable car back up to Murren (we found it too uphill from Gimmelwald to Murren). Bear in mind the queues up to Birg and Schilthorn can be long, so basing ourselves in Murren was a good idea as it was just a stroll to the cable car station. Compared to a longer ride and transfers from Wengen.
It's also nearer if you want to do the Lauterbrunnen valley walk to Stechelberg (which then brings up back up to Murren by cablecar). We also enjoyed the views up at Allmendhubal which is a 10-15min easy walk from Murren station.
That's what we did on our 2nd trip - enjoying the alps from a distance in Wengen and the mts. very close upfront in Murren. It's pretty cool that the cable ride from Lauterbrunnen to Grutschalp to Murren has a special carriage only for luggages. When riding from Grutschalp to Murren - definitely sit on the left.
From what I read, BO is not as expensive as Zermatt. So if that is true, you will get more for your money if you get the Jungfrau Travel Pass and just enjoy the region.
We always travelled off peak in mid-end September to avoid crowds and still enjoy the cool weather. Since you are travelling in July, I have no idea what the experience will be like as there will be more tourists and it may sometimes be a little stressful trying to get a seat on the trains. So best to get to the station earlier.
We chose to buy the First Class Half Fare Card online and also booked our train tickets on the main routes in advance before we left for Switzerland. Since I was sure of where we were staying I was able to buy and book those routes eg. Zurich Airport - Bettmeralp; Bettmeralp - Wengen; Murren - Engelberg; Engelberg - Zurich Airport.
Sitting in First Class took away the hassle of looking for seats which can be quite packed at times. We learnt this from our 1st trip. As for comfort, both 2nd and 1st class are great. It's just that one has a better chance of getting seats together and getting luggage space simply because less people are willing to pay for First Class. But there are more carriages for 2nd class and just one or two for First class.
Since yours is a fairly big group (I am not sure about discounts for the children) - it will add up to your cost if in First Class. We were 3 adults and at this stage of our lives, can afford to pamper ourselves a little more just to take away the stress and hassle of getting on trains and worrying about luggage space or seats. Hopefully you won't have too much of a problem when you travel.
Thanks to fellow forumers who guided me on the transport - everything worked out fine (except for the unexpected power failure where we had to get off the train).